Bioaugmentation Reduces H₂S in a Collection System

Collection System: 0.005 MGD

Hydrogen Sulfide Problems in Wastewater Collection Systems

Hydrogen sulfide (H₂S) is a common problem in wastewater collection systems and can create significant operational, infrastructure, and safety concerns.

H₂S forms when sulfate-reducing bacteria (SRB) break down organic material under anaerobic, or oxygen-limited, conditions.

As hydrogen sulfide accumulates, it can produce strong odors and contribute to corrosion throughout wastewater infrastructure.

How H₂S Causes Sewer Corrosion

Hydrogen sulfide released into the sewer atmosphere can undergo biological and chemical reactions that contribute to the formation of corrosive acids.

Over time, these conditions can damage:

  • Sewer pipes
  • Force mains
  • Lift stations
  • Manholes
  • Concrete structures
  • Other collection system infrastructure

Reducing H₂S concentrations can therefore help wastewater utilities protect equipment and extend the service life of collection system assets.

Hydrogen Sulfide Safety and Odor Concerns

In addition to corrosion, hydrogen sulfide can create strong, unpleasant odors around wastewater infrastructure.

At elevated concentrations, H₂S can also present serious health and safety risks for wastewater and sewer workers.

For these reasons, wastewater managers actively monitor and control hydrogen sulfide levels in collection systems.

Using Bioaugmentation for H₂S Reduction

Bioaugmentation can be used as part of a biological strategy to help reduce conditions that contribute to hydrogen sulfide production.

Introducing selected microbial populations into wastewater collection systems can help increase competition for available organic material and support a more balanced microbial community.

This approach may help reduce:

  • Hydrogen sulfide concentrations
  • Sewer odors
  • Corrosion potential
  • Collection system maintenance requirements

ProBiotic Scrubber® OCC for H₂S Control

The following case study describes the use of BioLynceus® ProBiotic Scrubber® OCC (PBOCC) to reduce hydrogen sulfide in a 0.005 MGD wastewater collection system.

The biological treatment program was designed to support H₂S reduction, odor control, and improved collection system conditions.

Figure 1. Corroded manhole after eight years with H2S concentrations of 100-1,200 ppm (Retrieved at https://www.miwea.org/docs/Keys%20Presentation.pdf).

Treating Hydrogen Sulfide in the Collection System

BioLynceus® ProBiotic Scrubber® OCC (PBOCC) was recommended to the MDWCA to help reduce hydrogen sulfide (H₂S) concentrations in the force main and downstream manholes.

The bioaugmentation program began in August at the lift station upstream of the force main.

PBOCC was applied daily through a feed pump operating at a low dosing rate. The product contains live bacterial cultures selected to support collection system treatment by helping reduce conditions associated with:

  • Sulfate-reducing bacteria (SRB)

  • Hydrogen sulfide production

  • Fats, oils, and grease (FOG)

  • Organic debris accumulation

H₂S Levels Decreased Within One Month

Within approximately one month of treatment, OdaLog monitoring data showed that H₂S concentrations in the force main headspace had consistently decreased to below 100 ppm.

Hydrogen sulfide levels in the manholes were also reduced to approximately 25 ppm.

Operators also observed a reduction in sulfide-related odors throughout the collection system.

Supporting Odor Control and Infrastructure Protection

Lower H₂S concentrations provided the MDWCA with both operational and infrastructure benefits.

Reducing hydrogen sulfide can help limit the conditions that contribute to corrosion in force mains, manholes, lift stations, and other wastewater infrastructure.

The treatment program resulted in:

  • Lower force main H₂S concentrations

  • Reduced manhole H₂S levels

  • Fewer sulfide-related odors

  • Improved collection system conditions

  • Reduced potential for long-term corrosion

The MDWCA was pleased with the reduction in hydrogen sulfide because improved H₂S control can help protect the structural integrity and extend the service life of collection system infrastructure.

Figure 2. Removed section of force main before (top) BioLynceus® PBOCC treatment and after (bottom) six months of applications. The treated pipe section had considerably less FOG buildup.

Additional FOG Reduction in the Force Main

An additional benefit of the ProBiotic Scrubber® OCC (PBOCC) treatment was a noticeable reduction in fats, oils, and grease (FOG) buildup within the force main.

Six months after treatment began, a section of the force main was removed and inspected. When compared with a pipe section removed before treatment, the MDWCA observed approximately 2 inches less FOG accumulation inside the line.

Reducing grease buildup helped improve wastewater flow and decreased the amount of material restricting the force main.

Improved Collection System Performance

Overall, bioaugmentation with PBOCC helped the wastewater collection system achieve:

  • Lower hydrogen sulfide (H₂S) concentrations

  • Reduced sulfide-related odors

  • Less FOG accumulation

  • Improved flow through the force main

  • Better overall collection system conditions

The reduction in FOG was an additional operational benefit beyond the original goal of controlling hydrogen sulfide and odor.

Supporting H₂S and FOG Control with ProBiotic Scrubber® OCC

BioLynceus® ProBiotic Scrubber® OCC is designed to support hydrogen sulfide reduction, odor control, FOG management, and improved wastewater collection system performance.

Reference

  1. Gerardi, M. (2016). Wastewater Bioaugmentation and Biostimulation. Lancaster, Pennsylvania: DEStech Publications, Inc., pp. 20–21.
    Wastewater Bioaugmentation and Biostimulation